Induced-draft plant



F- FINSTERBUSCH.

v INDUCED DRAFT PLANT. APPLICATION FILED JULY 16, 1914.

1,40 ,952, Patented Feb. 14, 1922-.

FRANZ EINSTERBUSCE, CHABLOTTENBURG, NEAR BERLIN, GERMANY.

INDUCED-DRAFT PLANT.

Specification of Letters Patent.

Patented Feb. 14, 1922.

Application filed July 16, 1914. Serial No. 851,284.

(GRANTED UNDER THE EROVISIQNS OF THE ACT 0E MARCH 3, 1921, 41 STAT. L., 1313.)

T 0 all whom it may concern."

Be it known that I, FRANZ Fmsrna nUsoH, engineer, residing at 76 lVilmersdorfstn, Oharlottenburg, near Berlin, Kingdom of Prussia, have invented certain new and useful Improvements in InducedDraft Plants, of which the following is a specification.

My invention relates to plants for producing induced draft.

In direct-acting mechanical induced draft plants it is necessary that when the fan is shut down the furnace can be worked solely by the natural draft of the smoke-stack. As the natural buoyancy of the smoke causes hardly any appreciablequantities of gas to pass through the fan, as is known, in consequence of its blade wheel and its general construction, it has heretofore been necessary to adopt one of the two following 6X- pedients: either the fan was placed adj acent to the smoke-stack and both the suction branch of the fan and the chimney were put into communication with the uptake, the one or the other connection being alternately closed, or the smoke-stack was placed on the outlet of the fan. In the latter case the smoke-stack was connected with the uptake solely by means of the fan and therefore for working with the natural draft a by-pass had to be provided connecting the uptake with the smoke-stack.

Both of these known arrangements have serious disadvantages. In the former, it is necessary to provide a connecting branch between the outlet of the fan and the smokestack, which of course results in considerable deviation of the direction of flow of the gases leaving the fan. Consequently more power is required owing to the frictional resistance. In addition, such a discharge pipe renders it impossible to construct a proper diffuser extending from the outlet of the gases from the fanonwards, which is very important particularly in dircct-acting induced draft plants when the velocity of discharge is an important factor connected with the total pressure produced. Lastly, the space required by such plants is very large and frequently causes difliculties which cannot be overcome.

Owing to these disadvantages the other arrangement, in which the smoke-stack is erected directly at the outlet of the fan will action is for the most part spoiled in consequence of the change of section at this place and the currents which are thereby caused.

Owing to the by-passopening into the smokestack the diffuser- The change from working with the fan to" natural draft can be made only by actuating. several dampers. In addition, owingto the large dimensions of the plants which are used at the present day the provision of suitable foundations for the smokestac.k is fre quently an exceedingly difficult matter. The arrangement first described. above has nevertheless frequently been adopted in spite of the defects attaching to it.

A primary object of this invention is to provide an induced draft plant which combines in a very simple manner the advan tages of both the known arrangements, without possessing their disadvantages.

According to the invention the lower part of the smoke-stack itself forms the delivery part of the fan, that part of the spiral cas ing of the fan which is located in the smokestack itself constituting the means for reversing from induced to natural draft.

To these ends, the invention consists in the construction, arrangement and combination of parts described hereinafter and pointed out in the claim.

One illustrative embodiment of the invention and a modification thereof are represented by way of example in the accompanying drawing, wherein Fig. 1 is a front elevation showing one form of my improved induced draft plant,

Fig. 2 is a side elevation thereof, and

Fig. 3 is a front elevation of a modified form comprising a suction branch of modified shape.

Referring to the drawing, a designates the smoke-stack of the plant, I) the part of the casing of the fan not constituted by the base of the smoke-stack, c the suction branch, and (Z that part of the spiral casing of the fan which is located in the base of the smokestack and is arranged rotatable about the fulcrum e byineans of any suitable device. According to the requirements of each case the suction branch 0 may be arranged desired. In Fig. 1 it is shown directed vertically downwards, whilst in Fig. 3 it is shown directed laterally so that the inlet of the branch is approximately flush with the bottom of the smoke-stack.

According to this invention the casing proper of the fan extends only up to the plane f shown in Fig. 1, whilst the part of the casing located to the right thereof is constituted by a specially designed base of the smoke-stack itself, the two parts being connected together in a very simple manner by flanges or other suitable means. In this manner very considerably increased safety of working is obtained, because a perfect connection of the fan with the smoke-stack, securely erected on its base, is assured such that the fan can be readily removed if necessary from the Smokestack and readily replaced and connected again. On being re moved the blade-whee]. of the fan is at once exposed and can be examined without difficulty.

If the furnace is to be worked by means of the fan the member d will be placed into the outer position shown by a dotted line in Fig. 1. The smoke will then enter by way of the suction branch into the fan, pass through the same and be blown by it, without any loss due to change of direction, into the Smokestack a. If the fan is to be shut down and the natural draft only is to be employed it is only necessary to move the member at over into the inner position shown by the dot-and-dash line in Fig. 1, so that the smoke can enter at once into the smokestack from below without any change of direction of flow. In addition, the member 03 which thus constitutes a damper can be placed in any desired intermediate position. In this manner the action of the fan or of the induced draft plant can be regulated in a very suitable manner.

It is to be understood that the invention is not limited to the movement of the member cl being a rotatory movement about the line 6, but that I may use any mechanical equivalent movable outwards in suitable manner for the purpose of changing from induced draft to natural draft due to the current of gases rising owing to their nat ural buoyancy without departing from the scope of the invention.

I claim V In an induced draft plant for furnaces, the combination with a smoke stack having an opening adjacent the base thereof, of a casing comprising spirally arranged walls, said casing having open ends, one of said open ends being fitted to the opening at the base of the smoke stack, a plate curved to conform with the spiral walls of the casing, said plate having one of its edges pivotally connected to one of the walls of the casing, the free end thereof adapted to move into engagement with the walls of the opening of the smoke stack, whereby the area of the passageway between the casing and smoke stack is varied.

In witness whereof, I have hereunto signed my name in the presence of two subscribing witnesses.

FRANZ FINSTERBUSCH.

Witnesses:

HEINRICH Kkiironowlrz, EMILY GEORGE. 

